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相关论文: Dependence of Galactic Halo Kinematics on the Adop…

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We explore the stellar metallicity distribution function of the Galactic halo based on SDSS ugriz photometry. A set of stellar isochrones is calibrated using observations of several star clusters and validated by comparisons with…

We study the metallicity distribution and kinematic properties of 4,680 A/F/G/K-type giant stars with $|z|>$ 5 kpc selected from the LAMOST spectroscopic survey. The metallicity distribution of giant stars with 5 $<|z|\leqslant$ 15 kpc can…

星系天体物理 · 物理学 2018-08-15 Shuai Liu , Cuihua Du , Heidi Jo Newberg , Yuqin Chen , Zhenyu Wu , Jun Ma , Xu Zhou , Zihuang Cao , Yonghui Hou , Yuefei Wang , Yong Zhang

We obtain a new determination of the metallicity distribution function (MDF) of stars within $\sim5$-$10$ kpc of the Sun, based on recently improved co-adds of $ugriz$ photometry for Stripe 82 from the Sloan Digital Sky Survey. Our new…

Here we study the metallicity bias in the velocity dispersions, the derived quantity called anisotropy and the mean azimuthal velocity profiles of the Milky Way stellar halo using Blue Horizontal Branch (BHB) stars taken from SDSS/SEGUE…

星系天体物理 · 物理学 2013-02-18 P. R. Kafle , S. Sharma , G. F. Lewis , J. Bland-Hawthorn

Based on Sloan Digital Sky Survey (SDSS) photometric data, Gu developed a new Monte-Carlo-based method for estimating the stellar metallicity distribution functions (MDFs). This method enables a more reliable determination of MDFs compared…

星系天体物理 · 物理学 2019-06-05 Jiayin Gu , Cuihua Du , Wenbo Zuo

The first and second moments of stellar velocities encode important information about the formation history of the Galactic halo. However, due to the lack of tangential motion and inaccurate distances of the halo stars, the velocity moments…

Here we present a kinematic study of the Galactic halo out to a radius of $\sim$ 60 kpc, using 4664 blue horizontal branch (BHB) stars selected from the SDSS/SEGUE survey, to determine key dynamical properties. Using a maximum likelihood…

星系天体物理 · 物理学 2012-12-04 Prajwal R. Kafle , Sanjib Sharma , Geraint F. Lewis , Joss Bland-Hawthorn

We analyse the structure of the local stellar halo of the Milky Way using $\sim$ 60000 stars with full phase space coordinates extracted from the SDSS--{\it Gaia} catalogue. We display stars in action space as a function of metallicity in a…

星系天体物理 · 物理学 2018-03-30 G. C. Myeong , N. W. Evans , V. Belokurov , J. L. Sanders , S. Koposov

We developed a new selection method of halo stars in the phase-space distribution defined by the three integrals of motion in an axisymmetric Galactic potential, ($E$, $L_z$, $I_3$), where $I_3$ is the third integral of motion. The method…

星系天体物理 · 物理学 2021-03-03 Daniela Carollo , Masashi Chiba

Halo stars orbit within the potential of the Milky Way and hence their kinematics can be used to understand the underlying mass distribution. However, the inferred mass distribution depends sensitively upon assumptions made on the density…

星系天体物理 · 物理学 2015-06-22 Prajwal R. Kafle , Sanjib Sharma , Geraint F. Lewis , Joss Bland-Hawthorn

We explore the origin of the observed decline in [O/Fe] (and [Mg/Fe]) with Galactocentric distance for high-metallicity stars ([Fe/H] > -1.1), based on a sample of halo stars selected within the Apache Point Observatory Galactic Evolution…

Modelling perturbations of the Milky Way (MW) halo induced by the infall of the Large Magellanic Cloud (LMC) offers new avenues to constrain the dark matter (DM) distribution in our Galaxy. A key observable is the reflex motion of the MW…

星系天体物理 · 物理学 2025-08-08 Rashid Yaaqib , Michael Petersen , Jorge Peñarrubia

We develop a flexible set of action-based distribution functions (DFs) for stellar haloes. The DFs have five free parameters, controlling the inner and outer density slope, break radius, flattening and anisotropy respectively. The DFs…

星系天体物理 · 物理学 2015-09-30 A. A. Williams , N. W. Evans

Recent analysis of the SDSS-III/APOGEE Data Release 12 stellar catalogue has revealed that the Milky Way's metallicity distribution function (MDF) changes shape as a function of radius, transitioning from being negatively skewed at small…

We use K-giant stars selected from the LAMOST DR5 to study the variation of the rotational velocity of the galactic halo at different space positions. Modelling the rotational velocity distribution with both the halo and disk components, we…

星系天体物理 · 物理学 2020-08-26 Hao Tian , Chao Liu , Yougang Wang , Yan Xu , Chengqun Yang , Bo Zhang , Xiang-Xiang Xue

We present a comprehensive study of the chemical properties of the stellar haloes of Milky-Way mass galaxies, analysing the transition between the inner to the outer haloes. We find the transition radius between the relative dominance of…

宇宙学与河外天体物理 · 物理学 2014-03-05 P. Tissera , T. Beers , D. Carollo , C. Scannapieco

We improve the identification and isolation of individual stellar populations in the Galactic halo based on an updated set of empirically calibrated stellar isochrones in the Sloan Digital Sky Survey (SDSS) and Pan-STARRS 1 (PS1)…

星系天体物理 · 物理学 2021-02-10 Deokkeun An , Timothy C. Beers

We present a low metallicity map of the Milky Way consisting of $\sim$111,000 giants with $-3.5 \lesssim$ [Fe/H] $\lesssim -$0.75, based on public photometry from the second data release of the SkyMapper survey. These stars extend out to…

星系天体物理 · 物理学 2021-04-28 Anirudh Chiti , Mohammad K. Mardini , Anna Frebel , Tatsuya Daniel

We measure the kinematic signature arising from the Milky Way (MW) disc moving with respect to the outer stellar halo, which is observed as a dipole signal in the kinematics of stellar halo tracers. We quantify how the reflex motion varies…

星系天体物理 · 物理学 2024-02-21 Rashid Yaaqib , Michael S. Petersen , Jorge Peñarrubia
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